Chat-Application-Backend

Overview

This is the backend for a real-time chat application built using Node.js, Express, MongoDB, and Socket.io. The API provides authentication, messaging, and real-time communication features.

Setup

Prerequisites

• Node.js (Latest LTS version recommended)
• MongoDB (Local or Cloud)
• Postman or REST Client for testing APIs

Installation

1. Clone the repository:

   git clone https://github.com/Programming-Sai/Chat-Application-Backend.git
   cd Chat-Application-Backend

2. Install dependencies:

   npm install

3. Create a .env file in the root directory:

    PORT=
    MONGO_DB_URL=
    MONGODB_PASSWORD=
    MODE=development || production
    JWT_SECRET=
    CLOUDINARY_CLOUD_NAME=
    CLOUDINARY_API_KEY=
    CLOUDINARY_API_SECRET=
    FRONTEND_BASE_URL=
    BACKEND_BASE_URL=

4. Start the server:

npm run dev

The server should now be running on http://localhost:5000.

Project Structure

./Chat-Application-Backend/*
        ├─ src/*
        |       ├─ controllers/*
        |       |       ├─ auth.controllers.js
        |       |       └─ message.controller.js
        |       ├─ lib/*
        |       |       ├─ cloudinary.js
        |       |       ├─ db.js
        |       |       ├─ socket.js
        |       |       └─ utils.js
        |       ├─ middleware/*
        |       |       └─ auth.middleware.js
        |       ├─ models/*
        |       |       ├─ message.model.js
        |       |       └─ user.model.js
        |       ├─ routes/*
        |       |       ├─ auth.route.js
        |       |       └─ message.route.js
        |       └─ index.js
        ├─ tests/*
        |       ├─ auth.tests.http
        |       └─ message.tests.http
        ├─ .env
        ├─ .env_skeleton
        ├─ .gitignore
        ├─ package-lock.json
        ├─ package.json
        └─ README.md

API Endpoints

Authentication

Signup a new user

POST /api/auth/signup

Request Body:

{
  "fullName": "Test User",
  "email": "testuser@example.com",
  "password": "Test@123"
}

Sign in an existing user

POST /api/auth/signin

Request Body:

{
  "email": "testuser@example.com",
  "password": "Test@123"
}

Response:

• Returns a JWT token. Use this token for authenticated requests.

Check authenticated user

GET /api/auth/check

Headers:

Cookie: jwt=your_token_here

Logout user

POST /api/auth/signout

Headers:

Cookie: jwt=your_token_here

---

Messaging

Get all users for sidebar (excluding logged-in user)

GET /api/message/users

Get messages between logged-in user and another user

GET /api/message/{chat_user_id}

Send a new text message

POST /api/message/send/{chat_user_id}

Request Body:

{
  "text": "Hello, how are you?"
}

Send an image message

POST /api/message/send/{chat_user_id}

Request Body:

{
  "image": "https://example.com/sample-image.jpg"
}

---

WebSocket Events

User Connection

• Event: connection
• Data: { userId } (sent via socket.handshake.query.userId)
• Description: When a user connects, they are added to userSocketMap, and all online users are updated.

Get Online Users

• Event: getAllOnlineUsers
• Data: { userIds: [...] }
• Description: Broadcasts the list of all currently connected users whenever a user connects or disconnects.

User Disconnect

• Event: disconnect
• Description: Removes the user from userSocketMap and updates the online user list.

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